Swab



Patented Jan. is, 192i.,`

l reinste PATENT oFFica., y

HENRY ALFRE) PORTER, OlE LOS ANGELES, CALIFORNIA.

SWAB.

Application filed. March 16, 1926. Serial No. 95,005.

This invention relates to thel oil well industry and it relates particularlyto a-swab adapted for use in this industry.

rlhe principal use for a swab of the character of my invention is for removing iiuid, such as rotary mud which is employed during the drilling, from a well. When the well is drilled, a drill pipe is extended into the well having a bit at the lower end thereof, this drill being rotated by a rotary table ,at the surface of the ground, For the purpose of removing the cuttings of the bit from the bottom of the hole and elevating them to thesurface of the ground for reinforcing the walls of the well and for preventing a premature How of oil, rotary mud is pumped through the drill pipe to the bottom of the well, this rotary mud passing upwardly through the well to the surface of the ground outside the drill pipe. lVhen it is desired or advisable to remove this rotary mud or other fluid from the well, it is common practice to lower into the well a swab which consists of a packer having valve means which permits the swab to be "lowered through the casing. When the swab is elevated, the valve is :losed and the liquid above the packer is pulled upwardly above the swab.

It is an important object of this invention to provide a swab of this character which is so constructd that it cannot elevate an overload of fluid from a well.

Another object of this invention is to provide a swab in which all the parts thereof which are subjected to wear are reversible in position; therefore, the life of the swab is substantially doubled.

A still further object of this invention is to' provide a swab which is specially constructed for simplicity of parts, assembling and dismantling, and ruggedness. v

Other objects and advantages of .the in vention will be made evident hereinafter.

c .Referring to the drawing in which I illustratemy invention, j

Fig. 1 is a vertical section through a swab showing the dierent parts thereof in the positions they occupy during the lower'ing of the swab into the well.

Fi 2 is a section similar to Fig. 1 showing t e position offthe parts during the raiS- p -ing of the swab and theelevating of fluid from a well.

Fig. 3 is a fragmentary view showing the position of certain parts of the swab when it is overloaded.

Fig. 4 is a section taken onthe line lt-4 0f Fig. l.

The lform of the invention shown in the drawing consists of a stem 11 having a head 12 formedv at the upper end thereof, this head 12 having a lower shoulder 13 and a threaded pin 14:. The threaded pin 11 is provided for the purpose of attaching the swab to the lower end of a pipe or connector of a cable ysuch as may be used for lowering and raising the swab in a well. rlhe stem 11 near the lower end thereof is provided with an overload valve 15 having a valve face 16. The portion of the stem 11 between the shoulder 13 and the overload valve 15 is provided with flutes 17 which are provided for a purpose which will be explained later.

Surrounding the fluted portion of the stem 11is a sleeve 18, the central part of which is provided with a number of openings 1 9. Screwed tothe upper end of the sleeve 18 is an upper nut 21 which when the sleeve 18 is 1n upper position, as shown in Fig. 1, engages the lower shoulder 13 of the head 12. The nut 21 is provided with a chamber 23 which communicates with the opening through the sleeve 18 and has apertures 21 in the wall thereof, which communicate with the chamber 23 and the exterior of the nut so that' there may be a passage of fluid into the opening of the sleeve 18 even through the upper nut 21 is in engagement with the 1 lower shoulder 'i3 of the head 12. Screwed to the lower end of the sleeve 18 is a lower nut 25.

longitudinally extending Rigidly held between the upperand lower i nuts 21 and 25 is a packer lassembly indicated at 27. 1This packer assembly consists 'of end members 28 whichare substantially identical in construction. The outer faces of the end members are engaged by adjacent faces of the upper and lower nuts 21 and 25.

Extending between the end members 28 is a tube 30, the ends of which extend onto end members 28 and lsurrounding the tube 30 is an expansible rubber packer 33, the ends 34 of which are reduced in size and extend inside cylindrical lips 35 of the end members 28, whereby the rubber packer 33 is stably secured in place. v

- A bottom valve 34a surrounds the lower end of the stem 11, the bottom valve 34e having a passage 35L formed therethrough through which the lower end of the stem 11 extends. The central part of the passage 35a is connected to the exterior of the bottom valve34a by means of a plurality of radially extending openings 36. 4The valve member 34EL is made symmetric in its upper and lower parts having an upper and a lower seat 37 which are identical, andhaving an upper and a lower valve face 38 formed on an annular ridge 39, which are likewise identical. The lower end of the bottom valve 34a is engaged by a washer 40 which surrounds the lower'end of the stem 11, this washer 40 having a tubular extension 41. The lower end of the steml 11 is threaded, as shown in the drawing, and a nut 42 having a tubular projection 43 is advanced on the lower end thereof, being locked in place by a lock nut/45. As a further means of holding the nut 42 and also the lock nut 45 on the stem, a pin 46 is extended through the extreme lower end of the stem 11. Compressed'between the .washer 40- and the nut 42 is a coil spring 48 which likewise surrounds the lower end of the stem 11. The purpose of the spring 48 is to resiliently hold the upper of the seats 37 in engagement with the valve face 16 of the overload valve 15 at all times unless there is an overload imposed on the swab.

In Fig. 1 the sleeve 18, and of course the packer assembly 27. is shown in raised position and in Fig. 2 the sleeve and packer assembly yis shown in lowered position. .It is pointed out that when the sleeve is 1n lowered position a seat 49 formed at the lower end of the bottom nut 25 engages the upper of the valve lfaces 38 of the. bottom valve 34a. 'When in this position an enlarged opening 51 which communicates with the opening through the sleeve 18 is closed.

The operation of my invention is substantially as follows:

The swab is .connected lto the lower end of a cable line by means of which it is lowered into a well from which it is desired to remove fluid. By friction of the packer on the casing of the well or friction ofthe fluid the packer assembly 27 is moved into the position shown in Fig. 1 so that the upper nut 21 engages the shoulder 13 of the head 12. This removes the bottom valve 34a from engagement with the seat 49 of the lower nut 25 and therefore opens the opening through the sleeve 18. This permits the swab to b'e easily lowered, since the fluid displaced may flow through the sleeve 18 to a point above the swab. fWhen the depth is reached from which the fluid is to be raised, the cable to which" the swab is secured is pulled upwardly. The packer unit 27 by reason of friction is immediately lowered into the position shown in Fig. 2 and in a position to seat the bottom Valve 37 Leraars:

18 and the tube 30. 'This fluid exerts an outi ward pressure on the expansible rubber packer 33 through the openings 32 in the tube 30. For this reason, as the swab is elevated the packer will be expanded into this position shown by dotted lines 53 of Fig'. 2. This causes the packer to frictionally engage the inner walls of the casing of the well and therefore the swab acts as a plunger of a reciprocating pump. Ther swab iselevated to the upper end `of the well and the fluid situated thereabove is pulled upwardly therewith vand is taken from the top of the well casing. The swab of my invention may be set to carry a certain load of the fluid and if it is attached to elevate more than this load, the parts will operate in a manner to open the opening through the sleeve 1 8. For example, if the swab is lowered below a certain distance the fluid thereabove will be of too great a load for the swab to lift. 1When the swab moves upwardly the pressure of this load on the packer assembly 27 will be sufficient to move the packer assembly 27 downwardly relative to the stem 11 and against Ithe action of the elevated. As the load on the rswab decreases,

the'reaction against the coil spring 48 decreases and the valve 15 will gradually approach its seat 37. lVhen the weight of the fluid on the swab decreases to a maximum load intended to be carried thereby, the valve 1,5 will seat and the fluid will then be elevated to the surface of the ground.

By an adjustment of the nut 42 the resilientl pressure tending to seat the-overload valve 15 may be varied so that the swab may be caused to carry any load desired.

One important feature of my invention is that the swab is of simple construction and that the parts thereof are rugged. The stem l1 is made but slightly smaller than the opening through the tube 18 for the purlll() pose of strength. To give the opening through the tube 18 sufficient capacity, the stem 11 is provided with the flutes 17. The large stem with the iutes 17 1s stronger than a smaller stem having no flutes therein. Another important feature of the invention is that all of the parts which are subjected to wear are reversible in position. The packer asesmbly 27, the expansible rubber packer 33 of which is subjected to wear, may

e inverted by merely removing the lower nut and inverting it in position. The bottom valve 34a, as previously explained, is` made symmetric in its upper and lower halves and when wear takes place thereon, it may be inverted, thus renewing the faces thereof which are subjected to wear'. This is a desirable feature, since there are only a few parts of the packer which are subjected to any material wear. In ordinary packers it is necessary to replace the worn parts. This is expensive since some of the parts which are subjected to wear are quite large and cost considerable. In my invention there is, therefore, an appreciable saving and an exceedingly great amount of convenience.

` I claim as my invention:

1. In a swab of the class described, the combination of: a stem; a head near the upper end' of said stem; a sleeve surrounding said stem below said head; an upper nut attached to the upper end of said sleeve, said upper nut being adapted to engage said head when said sleeve is in raised position;

a lower nut attached to the lower end of said sleeve; a packer assembly secured on said sleeve between said upper and lower nuts; an overload valve formed on said stem; a bottom valve surrounding said stem said means vincludes a spring urging said bottom valve, and surrounding the lower end of said stem.

3. A combination as in claim 1 in which said packer assembly is reversible in position on said sleeve.

4. A combination as defined in claim 1 in which said stem is but slightly smaller than said sleeve and is provided with flutes to increase available opening through vsaid sleeve.

5. A combination as deliined in claim 1 in which said bottom valve is symmetric in its upper and lower halves so that it may be used in inverted position on said stem.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 10th day of March, 1926. Y

HENRY ALFRED PORTER. 

